WK 1: Cytoskeleton and Cell Movement

The cytoskeleton is a network of protein filaments that provides structure and support to cells. It also plays a crucial role in cell movement and intracellular transport.

Diabetes is not caused by mutations or 'poisoning' of the cytoskeleton. It is a metabolic disorder characterized by high blood sugar levels due to inadequate insulin production or action.

Actin filaments, a key component of the cytoskeleton, are essential for muscle contraction. Their interaction with myosin allows for the sliding filament mechanism that drives muscle movement.

Vincristine, a chemotherapy drug, targets the cytoskeleton by interfering with microtubule function. This disruption disrupts cell division and growth.

Microtubules are hollow cylindrical structures with a diameter of 25 nanometers. They are composed of alpha and beta tubulin subunits arranged in a helical pattern.

Microtubules are involved in cell movement by powering the beating motion of cilia and flagella. These structures are critical for locomotion and fluid transport in various organisms.

Gout is not a result of cytoskeleton dysfunction. It is a type of arthritis caused by the accumulation of uric acid crystals in the joints.

Taxol, a chemotherapy drug, targets microtubules by promoting their stabilization, preventing their depolymerization, and inhibiting cell division.

Tau, a protein, plays a crucial role in stabilizing microtubules. Its misfolding and aggregation contribute to the development of neurodegenerative diseases such as Alzheimer's.

Kartagener Syndrome is a genetic disorder caused by mutations in genes responsible for cilia and flagella function. It can lead to respiratory problems and infertility.

Myosin II, a motor protein, plays a crucial role in cell crawling by contracting and pulling the cell in the direction of actin filaments. This coordinated movement helps the cell move across surfaces.

Dysregulation of microfilaments in cancer cells can lead to metastasis, the spread of cancer cells to distant sites. This can happen due to altered cell adhesion and migration.

Intermediate filaments, a type of cytoskeletal filament, extend from the perinucleus to the cell periphery. They provide mechanical strength and stability to the cell's internal structure.

Skin disorders can result from dysfunction of intermediate filaments. These filaments play a crucial role in maintaining skin integrity and structural support.

All of the above drugs target microtubules, either by stabilizing them (Taxol) or inhibiting their polymerization (Vincristine). These drugs interfere with cell division and are commonly used in cancer therapy.

Dynein motor proteins move along microtubules towards the negative (-) end. This movement is essential for transporting cargo, such as vesicles, towards specific cellular locations.

Microtubule Associated Proteins (MAPs) are a diverse group of proteins that interact with microtubules, contributing to their stability, arrangement, and function. They act as 'bridges' between microtubules and other cellular components.

Microtubules exhibit dynamic instability, a process of alternating periods of polymerization (growth) and depolymerization (shrinkage). This dynamic behavior allows for rapid changes in cell structure and function.

Kinesin motor proteins move along microtubules towards the positive (+) end. This movement is crucial for transporting cargo, such as vesicles and organelles, away from the cell body.

The internal diameter of a microtubule is 14 nanometers. This hollow lumen is essential for its structure and function, allowing for the passage of molecules and proteins.

Capping proteins attach to the ends of microfilaments, preventing further polymerization and maintaining the stability of the filament. They help regulate cell shape.

Myosin uses ATP hydrolysis as an energy source to move along microfilaments. This process generates the force needed for muscle contraction and other cellular movements.

Actin-ATP polymerization leads to the formation of F-actin, a filamentous actin structure. This process is crucial for cell shape, movement, and muscle contraction.

Gelsolin is a protein that severs microfilaments by breaking them into shorter fragments. This helps regulate the organization and dynamics of the actin cytoskeleton.

Microfilaments play a key role in maintaining cell shape. They form a network that provides structural support and allows cells to resist deformation and maintain their integrity.